Uncommonly Known Characteristics of Keyblades
A keyblade can be of varying strengths, depending on things such as the circumstances of its creation; think of it the same way as how a weapon can vary in strength depending on how it's been made. The keyblade's strength effects things such as its own durability and its effectiveness within certain situations.
The strongest known keyblade from Kingdom Hearts canon is the X-blade, the exact same keyblade Master Xenahort seeked to create. It glows brightly when summoned, a glow that lasts for several seconds, far longer than any other keyblade, and is the only known keyblade that can summon forth the titular Kingdom Hearts and control it.
It's possible for a keyblade to be damaged, incomplete or destroyed. A damaged or incomplete keyblade would look off in some manner, such as a cloud-like haze running over it. A destroyed keyblade disappears as though dismissed, but can't be summoned forth again, as it ceases to exist.
Contrary to what they may seem, keyblades are not magical devices;